1. Field of the Invention
The present invention relates to a rotary electronic component that constitutes an input operation section of electronic equipment and also relates to a method of manufacturing the electronic component.
2. Background Art
Hereinafter will be described a rotary encoder with a general-purpose structure as an example of a conventional rotary electronic component, with reference to drawings. FIG. 18 is a sectional view of a conventional rotary encoder. FIG. 19 shows an essential part of the encoder where a bearing and an operation shaft are being assembled.
Die-cast bearing 1 is attached to the upper portion of resin case 10. Die-cast operation shaft 2 formed into a rod shape has column section 2A that fits in round central hole 1A of bearing 1. Operation shaft 2 is rotatably held by the bearing and also movable in a direction axially of the shaft. Operation shaft 2 contains large-diameter section 2E in its upper portion and small-diameter section 2B in its middle. Small-diameter section 2B has C-shaped fixing ring 4 having a diameter larger than central hole 1A. Fixing ring 4 prevents operation shaft 2 from coming-off upwardly.
Operation shaft 2 fits in central hole 1A from the upper side of bearing 1 as shown in FIG. 19, and then operation shaft 2 is fixed by fixing ring 4 that is inserted onto the shaft from the lower side of bearing 1 and settles at small-diameter section 2B as shown in FIG. 18.
Operation shaft 2 has non-circular (in cross-section) area 2C in its lower portion. Rotator 6 of encoder 5 has an engagement with non-circular area 2C. Rotation of non-circular area 2C is carried to rotator 6, whereas movement in an axial direction of non-circular area 2C is not carried to rotator 6. Tip 2D of operation shaft 2 is in contact with movable contact 8 with springiness in push-switch section 7. Thus movable contact 8 urges operation shaft 2 upwardly, and accordingly, fixing ring 4 has an intimate contact with the periphery of central hole 1A of bearing 1.
Spring 9 is fixed under bearing 1 in a manner that a downwardly extending elastic arm of spring 9 elastically contacts an unevenness section that is radially formed on the upper surface of rotator 6. Spring 9 produces not only a torque during the rotation of rotator 6 but also a clicking feeling in response to a rotary operation through a predetermined angle.
To use such a conventional rotary encoder with a push switch as described above, knob 3 is disposed on large-diameter section 2E at the upper portion of operation shaft 2. When a user rotates knob 3 to rotate operation shaft 2, rotator 6 is also rotated. The rotation allows encoder 5 to generate a pulse signal, which is obtained via terminals 10A and 10B. When the user pushes operation shaft 2 by pushing down knob 3, electrical connections are established between terminals 8A in push-switch section 7. Such a rotary encoder is disclosed in, for example, Japanese Patent Unexamined Publication No. H10-64375.
Such a conventional rotary electronic component (i.e., a rotary encoder) is employed for an input operation section of electronic equipment. However, the structure of the input operation section varies depending on the equipment; in particular, the height between knob 3 and the wiring board on which the rotary electronic component is mounted varies depending on the structure of each input operation section. Accordingly, the length of operation shaft 2 has to be changed so as to fit with each structure of the electronic equipment.